1. Field of the Invention
The present invention relates to a method for measuring a weight of a load carried by a vehicle, typically dump trucks, the body weight of which is supported by suspension cylinders.
2. Description of the Prior Art
In a prior art measuring method a weight of a load carried by such vehicles (hereinafter called load weight) with a vehicle bearing type weighing instrument, typically a platform weighing machine, the weight of an empty vehicle is subtracted from the weight of a loaded vehicle to obtain the load weight. In the measurement of the above loaded vehicle weight and the empty vehicle weight, the weight applied to each suspension cylinder is obtained as a product of the pressure in the suspension cylinder and the cross-sectional area of the cylinder, and the weight of the loaded or empty vehicle is obtained from the total value of weights applied to four suspension cylinders. Of course, this measurement is performed with the suspension cylinders in the stationary state.
The load weight measurement by the above-mentioned prior art method has produced measurement errors around .+-.25% at the maximum due to the effects of sliding resistance of the piston cylinder of the suspension cylinder and a longitudinal tilt of the vehicle body.
Since vehicles such as dump trucks are mostly used for transporting rocks, ores, etc., to know the weight of load accurately is very important for preventing vehicle damage due to overloading as well as performing the control of the amount of products.